A bifold door is a type of door comprising two door panels which are joined to one another along a centre hinge. When the door is closed, the door panels extend at an angle of 180.degree. to one another. When it is opened, the door panels hinge with respect to one another about the centre hinge, in the manner of a jack-knife, to extend at an angle of 0.degree. or close to 0.degree. with respect to one another.
Bifold doors are designed to open either to the right or to the left. A bifold door that has been designed for use in a left-opening configuration cannot, after it has been installed, be changed from one configuration to the other. This makes bifold doors inflexible in their installation and use. It is also difficult to clean them at the fixed end thereof and areas surrounding the fixed end.